Rotary tablet-machine.



F. J. STOKES.

ROTARY TABLET MACHINE.

APPLICATION FILED NOV.30.19|4.

1 89 ,570, Patented Dec. 31, 1918.

2 sH'EETs-sHEET L w/r/vasses; awe/Wok F. J. STOKES.

ROTARY TABLET MACHINE. APPLICATlON FILED NOV. 30.

Patented Dec. 31, 1918.

2 SHEETS-SHEH 24 P m m w mm "mm m m f WWI-MIA C n a @W FRANCIS J.STOKES, 0F EHILADELPHIA, PENNSYLV i ROTARY TABLET-MACHINE.

Specification of Letters Patent.

Patented Dec. 31, 11918.

Application filed November 30, 1914. Serial No. 874,618.

To all whom it may concern:

Be it known that I, FRANCIS J. STOKES, a citizen of the United States,and a resident of Philadelphia, in the county of Philadelphia and Stateof Pennsylvania, have invented certain new and useful Improvements inRotary Tablet-Machines, of which the following is a specification.

The present invention relates to improvements in rotary tablet machinesof the general type or style shown and described, for example, inLetters Patent of the United States No. 610,029 of August 30th, 1898, toE. C. Clark for a powder compressor, and the principal objects of thepresent invention are, first, to compress or make into tablets materialswhich need not have lubricating substances previously incorporated ormixed with them; second, to provide for accurately determining the sizeor quantity of the material in each tablet; third, to make purer andmore uniform tablets; fourth, to simplify the preparation of thematerials,

- and fifth, to avoid defects in and increase the efiiciency of suchmachines.

The invention will be claimed at the end hereof, but will be firstdescribed in connection with the embodiment of it chosen forillustration in the accompanying drawings, in which- Figure 1, is a sideview, partly in section, of so much of a rotary tablet machine as isnecessary to illustrate features of the invention embodied therein.

Fig. 2, is a top or plan view, partly in section, of the mechanismillustrated in Fig. 1.

ig. 3, is a sectional view, drawn to an enlarged scale, and illustratingfeatures of the invention.

Fig. 4., is an elevational view of a part ofv the machine illustratingfeatures of the invention, and

Fig. 5, is a sectional view, taken on the line 5-5 of Fig. 2.

In the drawings 1 is a rotary head driven for example by means of theworm and worm wheel 2. This head is provided w1th apertures that extendclear through it and constitute molds 3. The head is provided with toppunches 4 and bottom punches 5 that cooperate with the molds 3. Punchesare omitted toward the right-hand part of Fig. 1 for the sake ofclearness. 6, is a feed frame that is fixed or stationary in respect tothe head and it serves to feed material other, and 9 is a cam surface orslide for raising the top punches 4, one after another. Cams raise thebottom punches at intervals.

Consldering'one pair of punches the operation is that the bottom punchis lowered,-

the top punch is raised, the material is introduced into the molds bythe feed frame, the bottom punch is raised to insure the presence of thepredetermined amount of material in the mold, the punches press thematerial into tablet form, the top punch is lifted, and the bottom punchis raised and ejects the tablet. The punches operate in succession andcontinuously, but a description of one is suflicient for anunderstanding. There is nothing particularly new so far as the presentdescription has gone.

11, are shakers consisting generally of a receptacle having a perforatedor reticulated discharge 12. They are pivoted and spring retracted andare arranged at the opposite ends of the feed frame 6 in such positionthat they are operated by a rotating part of the machine at theappropriate times. As shown the shakers are pivoted as at 13 to the endsof the feed frame 6 and they are provided with adjustable arms 14 andare controlled or retracted. by spring 15, and the arms are arranged inthe path of the top punches. A lubricant, as talcum powder, is suppliedto the shakers and as an empty mold approaches the filling frame, theshaker is operated in the manner described so as to deposit a littletalcum powder in the mold on top of the bottom punch. After the mold hasbeen filled, the other shaker deposits 'a little talcum powder on top ofthe material in the mold. The talcum powder prevents the punches fromsticking to the tablet and its use in the shaker avoids the necessity ofincorporating a much larger quantity of lubricant in the material priorto its being fed to the machine. The advantage of this is that thefinished tablet is purer for the amount of lubricant superficiallyapplied by the shakers is very small, and in fact, negligible in thetablet. A washer 16 is provided around each bottom punch and the washeris lubricated. As shown the rotary head is radially slotted as at 17 forthe application of lubricant to the washer. By these means the bottompunch is properly lubricated so that it does not stick inthe mold andthis is accomplished without requiring the admixture of lubricant withthe material that is compressed into tablets. The tablets are purer thanin cases where lubricant is previously mixed with them and furthermorethe preparation of the material which is fed to the machine issimplified, since no lubricant need be mixed with it. In the path of thelower punches there is inserted a shrouded cam 18 at the point where thebottom punches are to be lifted in order to eject any surplus materialfrom the mold prior to the descent of the top punch. As shown thisshrouded cam consists of a cylindrical member having a slot cut throughit for the passage of the head of the bottom punches and leavingoverhanging parts 19 under which the heads of the bottom punches run. Itis overhanging parts, like 19, that are referred to by the termshrouded. 20, is an adjusting screw having swivel connection with theshrouded cam so that the latter may be lifted and depressed while heldagainst turning by its pin 21. The advantage of the shrouded cam sectionis that when the machine is running rapidly the punches as they risetoeject surplus material do not overthrow or ascend too far by reason oftheir momentum. This makes the ejection of the proper amount of materialfrom the mold accurate and insures uniformity in the weight and size ofthe tablets.

From the foregoing description it will be understood that the purity ofthe tablets and their uniformity are increased. Necessarily some of thematerial will collect in and about the rotating head and might fall. Ifthe material is of value, as is often the case, it is conceivable thatsuch material may be returned to be made into tablets and in some casesit might not be desirable to permit the material to be thuscontaminated. The gutter 22, constituting an extension of the guard forthe gear wheel 2, is carried by the machine frame 23 and encircles therotating head to the extent necessary and receives any material that mayreach it, and from the gutter this material may be collected as by meansof the spout 24 and returned for reuse in uncontaminated condition. Thefeed frame 6 is fixed and it should be positioned close to the surfaceof the rotary head, which runs under it, yet jamming must be avoided. Asshown a part of the machine frame, for example, the gutter 22 isprovided with a fork 26 having inclined surfaces 27 and the feed frame 6is provided with a pin 28 having a tapered head 29 and a screw stop 30.The motion of the rotary head tends to shift the feed frame 6 toward theleft in Fig. 4, so that when the fork and head of the pin, or moreaccurately, the bevmeat-7c eled surfaces thereof, are in contact thescrew stop 30 limits the extent to which the feed frame can be drawndownward in such a way that jamming is avoided and accuracy of feedinsured. The necessary adjustment can be made by turning the screw stop.

The bottom punches are subject to wear and they must properly eject thetablets quite near the feed frame, and unless the tablets are properlyejected they tend to get back into the feed frame and hence bedestroyed. In the cam-way 10 and at the place where the tablets areejected there is provided an adjustable cam section 25 located at thehigh part of the cam so that it is this cam section 25 which controlsthe height to which the punches are raised in ejecting the tablets andby adjusting the height of this section 25 the ejection operation can beaccurately controlled.

From the foregoing description it is evident that the describedimprovements cooperate to provide uniform tablets of great purity and toobviate the possibility of accidental destruction of the tablets afterthey have been made.

'What I claim is:

1. In a rotary tablet machine the combination of a rotary head providedwith molds and punches, and a spr retracted pivotally mounted shakerhaving a perforated open bottom and disposed in the path ofrotation ofthe head, whereby the-shaker is periodically jarred as the head revolvesto shake some of its contents out of its per: forated bottom.

2. In a rotating tablet machine the combination of a rotary headprovided with molds and punches, means for reciprocating the punches inrespect to the molds, means for feeding the molds, and a pivoted springretracted shaker spaced angularly in advance and in rear of the feedingmeans and in range of the punches which collide with and turn and freethe shakers one before and the other after the feeding.

3. In a rotating tablet machine the combination of a rotary headprovided with molds and punches, a fixed feeding frame, and pivotalspring retracted shaker arranged at the end of the frame and in linewith the punches by which it is turned and released and jarred,substantially as described.

4. The combination in a rotary tablet ma chine of a rotary head and itsmolds and punches, a gear wheel on the head, mechanism for operatingsaid parts, a fixed feeder frame, nd a fixed gear guard provided with anoutward gutterarranged part way around the head and in prom'mity withthe feeder.

5. In a rotary tablet machine the combination of the machine frame, arotating head provided with molds, a feed frame fixed in respect to thehead and atits top surface, and a fork with inclined surfaces and a pinmeomo Q with tapered head and a, screw stop? interof engagement, and astop, substantially as 10 posedbetween the feed and machine frames.described.

6. In a rotary tablet machine the combi- In testimony whereof I havehereunto nation of the machine frame, a rotating head signed my name. a5 provided with molds, a feed frame fixed in FRANCIS J STOKES.

respect to the rotation of the head and arranged at its top surface,devices interposed Witnesses:

between. the machine frame and the feed M. T. MONTAGUE, frame andprovided with inclined surfaces M. A. WALTER.

